Android 9 Development Cookbook - Third Edition

Creating and monitoring a Geofence

If your application needs to know when the user enters or exits a certain location, there's an alternative to continuously checking the user location: Geofencing. A Geofence is a location (latitude and longitude) along with a radius. You can create a Geofence and let the system notify you when the user enters the location proximity you specified. (Android currently allows up to 100 Geofences per user.)

Geofence properties include:

• Location: The longitude and latitude
• Radius: The size of the circle (in meters)
• Loitering delay: How long the user may remain within the radius before sending notifications
• Expiration: How long until the Geofence automatically expires
• Transition type:
  • GEOFENCE_TRANSITION_ENTER ...